Because wakeboarders like big wakes, boats built for wakeboarding usually now have water tanks, called bladders installed near the back of the boat to increase boat weight or “displacement” and thus increase wake size. Patents cover various bladder configurations. One patent covers a totally different method of modifying a boat wake by placing a flat plate (called a “trim tab‘) at the bottom-center of the transom. This method can change the shape of the wake, but it is not intended or effective for increasing wake size, because trim tabs raise the back or “stern” of the boat and thus reduce wake size. Before I/O boat motor drives included automatic tilt controls, “trim tabs”, as shown in FIG. 1, were often installed on the bottom outside edges of the transom, to adjust not only the “trim” or bow/stern angle but also the list or port/starboard tilt. Most trim tabs are hydraulically controlled so that the driver can adjust the tilt of the boat while underway with a toggle switch. At slower speeds, when the bow tends to ride too high, the tabs are lowered, thus deflecting the water leaving the back of the boat downward and so providing lift to the back of the boat and lowering bow or “trim.” If the boat is listing to one side, the trim tab on that side can be adjusted lower until there is no more sideways tilt. (Control mechanisms, typically hydraulic, for adjusting trim tabs have been in use for over 50 years and are not a part of this invention).